PV-WAVE Foundation > Tutorial > Programming with PV-WAVE > Operating System and Environment Access
Operating System and Environment Access
Operating system commands can be executed from within PV-WAVE without quitting the current PV-WAVE session.
To execute a single operating system command from PV-WAVE, enter the dollar sign ($) followed by the desired operating system command.
Operating System Commands
*For example, to see a listing of files in the current directory (under UNIX), at the WAVE> prompt, type:
$ ls
The files in your current directory are displayed. In Windows, type $ dir.
*To enter multiple operating system commands and temporarily suspend PV-WAVE, type:
SPAWN
The operating system prompt appears.
Now you can enter operating system commands just as you normally would.
*To exit the operating system and return to PV-WAVE, at the operating system prompt, enter (for UNIX and Windows machines):
exit
Table 3-7: OS and Environment Access Commands lists some common OS and environment access commands that you may find useful when using PV‑WAVE.
 
OS and Environment Access Commands
Command
Description
$
By itself from the WAVE> prompt, spawns a child process to the operating system prompt. If followed by an operating system command, executes it then immediately returns to WAVE> prompt. Not for use in programs.
SPAWN
Spawns a child process to execute commands. Output generated by commands can be captured in a PV-WAVE variable. Can be used in programs (unlike $).
GETENV
Get value of an environment variable.
SETENV
Set value of an environment variable.
ENVIRONMENT
Returns a string array containing all the environment strings for the PV-WAVE process. (UNIX/Windows)
CD
Change current directory.
PUSHD
Push directory to top of LIFO directory stack.
POPD
Pop directory from top of LIFO directory stack.
PRINTD
List all directories in LIFO (Last-In-First-Out) directory stack, and current directory.
PWD
Prints the working directory.